\pgfplotsset{compat=1.5, width=7cm, height=6cm}

\begin{tikzpicture}[scale=1.2, every node/.style={transform shape}]

% Define parameters
\def\gammaparam{.6}
\def\tauparam{.4}
\def\etaparam{-2}
\def\height{5}
\def\width{8}

% Plot curves
\begin{axis}[axis lines=none, xmin=0, ymin=0, y=5.5cm, x=7cm, clip=false]
\addplot[name path=agglomeration,domain={0:.75},gray!60,semithick] {exp((-\gammaparam*\tauparam*x)/(1-\etaparam * x))} node[pos=1, right, yshift=0pt,xshift=-3pt,black]{$\widetilde{A}(c<0)$};
\end{axis}

\begin{axis}[axis lines=none, xmin=0, ymin=0, y=5.5cm, x=7cm, clip=false]
\addplot[name path=agglomeration,domain={0:.75},gray!60,semithick] {exp((-\gammaparam*\tauparam*x)/(1-(\etaparam+3) * x))} node[pos=1, right, yshift=-10pt,xshift=-6pt,black]{$\widetilde{A}(c>0)$};
\end{axis}

% Draw axes and lines
\draw (0,0) -- ({\width},0) node[midway, sloped, below=4pt] {$\phi$}
														node[at start, sloped, below=4pt] {$0$}
														node[at end, sloped, below=4pt] {$1$};
\draw[very thin]  (-.1,5.5) -- (.1,5.5);	%tick
\draw[very thin]  ({\width-.1},5.5) -- ({\width+.1},5.5);	%tick
\draw[->]  (0,0) -- (0,6) node[at end, left=10pt, below=5pt] {$\widebar{A}$};   %label
\draw[very thin]  ({\width-.1},{(1-\gammaparam)*5.5}) -- ({\width+.1},{(1-\gammaparam)*5.5});	%tick
\draw[->] ({\width},0) -- ({\width},6) node[right=3pt] at ({\width},{(1-\gammaparam)*5.5}) {$\underline{A}$};

\draw[dotted] (0,5.5) -- ({\width},{(1-\gammaparam)*5.5});
\draw (0,5.5) -- ({\width},{(1-\tauparam*\gammaparam)*5.5});

\draw [decorate,very thin,blue,decoration={brace,amplitude=6pt},xshift=1pt,yshift=0pt]
({\width+.02},{5.5-.025}) -- ({\width+.02},{(1-\gammaparam)*5.5 + .025}) node [blue,midway,xshift=10pt] 
{ $\gamma $};

\draw [decorate,very thin,blue,decoration={brace,amplitude=6pt, mirror},xshift=-1pt,yshift=0pt]
({\width-.02},{5.5-.025}) -- ({\width-.02},{(1-\tauparam*\gammaparam)*5.5 + .035}) node [blue,midway,xshift=-12pt] 
{ $\tau \gamma $};



\end{tikzpicture}
